Railway-traffic-controlling apparatus



Jan. 28,'1-930. R. A. MccANN RAILWAY TRAFFIC CONTROLLIG APPARATUS Original Filed Nov. 5. 1927 @GMA QSNNNNBY 3E@ LBGNU INVENTOR K Mc C40 n,

EDM Hirn, m47

Petepted Jan. 28, 1930 UNITED STATES PATENT OFFICE RONALD A. MOCANN, 'OF SWISSVALE, PENNSYLVANIA, AISSIGNGR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA RAILWAY-TRAFFIC-CONTROLLING APPARATUS Application led November 5, 1927, Serial No. 231,269. Renewed June 29, 1929.

My invention relates to railway traiiccontrolling apparatus of the type comprising train carried governing means controlled by characters l and l? designate the track rails of a stretch of railway track over which traffic moves in the direction indicated by the arrow. These rails are divided by means of insulated joints 2 into a plurality of successive track sections, of which only one section, A-B, is shown complete in the drawing. Train controlling current is supplied to the rails of this section from a suitable source of energy such as an alternator M. The current supplied to the trackway by this 'alternator may be of a frequency of the order of the usual commercial alternating current, such for example, as 60 cycles or 100 cycles per second.

The supply of current to the track rails is controlled by a code transmitting device comprising a plurality of rotatable cams each designated by the reference character O with a suitable distinguishing exponent. The

l, cams O are driven at a constant speed by a suitable motor J which is supplied with current from the alternator M. Thecam O1 is provided with a plurality of swells 5 spaced about its periphery, which swells successively operate a contact 6 to periodically close the contact as the cam O1 is rotated. In similar manner the cams O2 and O3 are provided with diiierent numbers of swells 5 which control contacts 7 and 8, respectively. One terminal of the alternator M is constantly connected with rail l of sec-I tion A-B; the other terminal of the alternatoris connected with the rail 1a through a current Alimiting impedance Z, and one of the contacts 6,l 7 or 8 depending upon tratlic conditions as`hereinafter explained.

It is manifest that the alternating current supplied to the rails of the trackway by alternator M is periodically varied at the frequency of operation of the contact of the code transmitting device interposed between the alternator and the track rail la. The code transmitting device may be constructed to cause such variations at any reasonable frequencies, but for purposes of illustration, I

will assume that the cams 0 are rotating at 2O revolutions per minute, that cam O1 has 4 swells, that cam O2 has 6 swells, and that cam O3 has 9 swells. The selection between the'several contacts of the coding device in accordance with tratiic conditions may be accomplished in any suitable manner, such, for example, as by means of a home relay 3 and a distant relay4. The circuits for controlling these two relays form no part of my present invention and are omitted from the drawing for the sake of simplicity. For present purposes, it is suiiicient to state that home relay 3 is normally energized but is de-energized when a train occupies the section immediately to the right of point B, and that distant relay 4 is also normally energized but is de-energized when a train occupies either the first or the second section immediately to the right of point B. When relays 3 and 4 are both energized, so that the front contacts of both these relays are closed, current from alterna-` rails over contact 8 operated by cam O3. Un-

der these conditions, the alternating current supplied to the trackway is periodically varied at a frequency of 180 cycles per minute. Current supplied to the trackway under these conditions, I will hereinafter term the clear code. When `relay 3 is energized and relay 4 is cle-energized, contact 7 controlled by cam O2 is included in the trackway circuit, and under these conditions the trackway is supplied with 100 cycle current interrupted at a frequency of 120 cycles per minute; this current I shall lhereinafter term the approach restricting code. In similar manner, when relay 3 is de-energized, a circuit is completed from alternator M to the track rails through contact 6 operated by cam O1, and the trackway is then supplied with 100 cycle current interrupted at a frequency of 8O cycles per minute, which current I will call the appreach code.

A train, indicated diagrammatically at V, is provided with a receiver designated in general by the reference character P. Thls receiver comprises two magnetizable cores 22 and 22", carried on the train in advance of the forward axle, and located in inductive relation with the two track rails 1 and 1, respectively. Core 22 is provided with a winding 23, and core 22 is rovided wlth a similar winding 23". The windings 23 and 23*I are connected in' series in such manner that the voltages induced therein by an alternating current flowing in opposite directions in the track rails at any instant are additive. The windings 23 and 23 are connected through a condenser 25 with the primary of an auto transformer L, and the circuit N comprising the above mentioned elements, which I will term the pick-up circuit, is tuned to resonance at the frequency of the alternating current in the trackway. The secondary circuit of the auto transformer L is tuned to resonance at the frequency of this current by la condenser 26. The periodically varying 100 cycle voltage across the terminals of condenser 26 is amplified and converted to low frequency alternating current by two electron tube amplifiers E1 and E2. The filaments of these tubes are connected in a series circuit including a ballast lamp 1l' and two control resistances 10 and 12, and this circuit is supplied with current from a suitable source such as' a battery 9. The secondary of the auto transformer L and the condenser 26 in parallel' therewith, are connected across the grid and filament of the tube E1 and also across the resistance 10 in the filament circuit, so that the grid is normally negative by several volts with respect to the filament of E1. The tube E]L is provided with a late circuit including a suitable source o high potential such 'as a battery 13, primary 14 of an interstage transformer K, the plate and filament of the tube El, and the resistance 10. The second stage tube E2 is provided with a plate circuit including the battery 13 and the primary 16 of a low frequency transformer Y. Secondary 15 of transformer K is connected across the gride and filament. of tube E2 in such manner that the grid normally, when no 100 cycle voltage is present, has a sufficient negative bias so that the plate current of tube Ez-is substantially zero. The secondary 17 of transformerY is connected directly with a olarized relay D, that is, a relay which is seectively responsive to the polarity of the current supplied thereto. The relay D controls apparatus which is selectively responsive to the frequency of operation of the relay. In the present embodiment of my invention, this apparatus is constructed as follows:

Associated with relay D is a transformer T comprising a primary 19 and a secondary 20. Direct current is supplied to the primary 19 of transformer T from a suitable source of energy such as a battery 28, and the supply of such current is periodically varied in d1- rection in accordance with the frequency at which relay D operates. As shown in the drawing, when relay Dis energized in one direction to close contact 18-18, current flows from battery 28 through the lower half of primar 19 in one direction, but when the relay is energized in the opposite direction so that contact 18-18b is closed, current flows from battery 28 through the upper half of primary 19 in the opposite direction. It follows that when relay D is a periodically reversed, the current in primary 19 of transformer T is periodically reversed at the frequency of the periodic variations in the trackway current. As a result of this, there is induced in the secondary 20 a low frequency alternating electromotive force, and this electromotive force is supplied to a plurality of circuits each designated by the reference character C with a distinguishing exponent. Circuit C3 is tuned, by a reactor 24 and a condenser 21, to resonance at the frequency of the clear7 code or 180 cycles per minute, and a relay R3 is connected across a portion of reactor 24 of circuit C3 through a rectifier h3. In similar manner, circuit C2 is tuned to resonance at the frequency of the approach restricting code or 120 cycles per minute, and a relay R2 is at times connected across a portion of reactor 24 of this circuit through a rectifier h2. A relay R1 is connected, through a rectifier h1 and a reactor 27, directly with secondary 2O of transformer T, and this relay is arranged to be'energized when relay D is receiving current of any of the train control code frequencies.

Associated with the relays R is a stick relay S. The relays R and S may control Uoverning means of any suitable type, whic as here shown is winding 55 of a magnet valve G arranged when energized to connect a reservoir 29 with a suitable source of fluid pressure not shown in the drawing. The reservoir 29 is connected with a relay valve H, so thatv when this reservoir is charged valve H occupies the position shown in the drawing and a pneumatic relay 31 is then connected by pipe 128 with a source of fiuid pressure so that contact 32 of this relay is closed. Pipe 128 also controls a brake application valve (not shown) for causing an application of the brakes when this pipe is connectedto atmosphere. lVhen winding 55 of valve G becomes de-energized, the reservoir 29 is connected with atmosphere through a restricted orifice 34 and also through a whistle 33 which gives an audible indication to the engineman. After a brief interval of time, such, for example, as 6 seconds, the pressure in reservoir 29 lli) i and pneumatic relay 3l closes its contact 32.

The train is also rovided with a manually operable acknowle ging switch a located at Ais some convenient place within the reach of the engineman, and comprising a normally closed contact 52 and a normally open contact 71. When the acknowledging switch is operated, contact 52 is opened and contact 71 is closed. Furthermore, a resetswitch, designated by the reference character r, and comprising a normally closed contact 53 and a normally open contact 106, is provided, and is located outside the cab Where it will be inaccessible to the engineman when the train is in motion.

The apparatus thus far described is disclosed and claimed in an a plication for Letters Patent of the United tates by Lloyd V. Lewis filedAugust 2, 1927, Serial No. 210,165 for railway trame controlling apparatus. rlhis specific apparatus is illustrated in the present application as a convenient means forv selectively supplying voltages to the output terminals of rectifiers h3, 71,2 and h1, and so to the control relays R3, R2 and R1, but any other suitable means for supplying these voltages could be used-without departing from the scope ofmy invention.

The operation of the apparatus is as follows:

I will first assume that the clear code is being supplied to the track rails, so that the trackway current is being interrupted at the frequency of 180 cycles per minute. Relay D therefore operates at therate of 180 cycles per minute, so that alternating current of this frequency is supplied by secondary20 of transformer T to the three circuits`C. Relay R3 is accordingly energized, but relay R2 is de-energized because its associated circuitC2 is not resonant at the frequency which is now being supplied to thiscircuit. Relay R1 is de-energized for a reason which will appear hereinafter. With relay R3 energized, current flows from battery 28, through wires 58 and 60, front contact 46 of yrelay R3, a clear lamp 41 and wire 59 to battery 28. The clear lamp 41 is included in a cab signal Q which also includes an approach restricting lamp 42, an approach lamp 43, and a slow lamp 44. The clear lamp l41 is therefore lighted to indicate clear. Current also flows from battery 28, through wires 58 and 60, front contact 66 of relay R3, wire 65, back contact 57 of acknowledging relay S,l contact 52 of the acknowledging switch a, contact 53 of the re-set switch r, winding 55 of magnet valve G, and wire 59 to battery 28. Magnet valve G is therefore energized, with the result that the train may proceed without an automatic application of the brakes.

I will next assume that a change occurs in traffic conditions which results in the approach restricting code of 120 cycles per minute being supplied to the trackway. f Relay R3 then becomes de-energized, because circuit C3 associated with this relay is not resonant at the code frequency now received by the control relay circuits.- The circuit for lamp 41 and the circuit for magnet valve G are therefore opened at front contacts 46 and 66, respectively, of relay R3, and if the engineer takes no action, an automatic application of the brakes willoccur at the expiration .of the time interval required for the pressure in reservoir 29 to reduce to such value that valve H reverses. If, however,

prior to the reversal of valve H, the engineer operates the acknowledging switch a, he may v forestall the automatic brake application. When contact 71 of the acknowledging switch a becomes closed, a pickup circuit for the acknowledging relay S is closed, which circuit is from battery 28, throughwires 58 and 60, back contact 46 of relay R3, back contact 35 of relay R2, back contact 37 of relay R1, contact 71 of acknowledging switch a, contact 32 of pneumatic relay 31, winding of relay S and wire 59 to battery 28. As soon as relay S becomes energized, a stick circuit for this relay 'becomes closed, which stick circuit passes from battery 28, through wires 58 and 6l), back contact 46 of relay R3, back contact 35 of relay R3, back contact 37 of relay R1, front contact 87 of relay S, winding of relay S, and vwire 59 to battery 28. It

gized, the engineer may release the acknowledging switch a.- When relay S becomes energized, it closes a circuit for relay R1, which circuit passesfrom the right-hand output terminal of rectifier 11,1, through the winding of relay R1 and front contact 50 of relay S to the left-hand output terminal of rectifier L1. Inasmuch as circuit C1 is not tuned, a voltage is created across the output terminals of rectifier H1 andso relay R1 becomes energized. As soon as relay R1 becomes energized, a stick circuit for this relay becomes closed, which circuit passes from the right-hand terminal of rectifier H1,

through the winding of relay R1, front conthe right-hand terminal of rectifier h2 through the windin of relay R2 and front contact 95 of relay 1 to the left-hand terminal of rectifier k2. Inasmuch as circuit C2 is resonant at the code frequency now s being supplied by transformer T, a voltage is created across the terminals of rectifier h1, so that rela R2 becomes energized. As soon as relay 2 becomes energized, a stick circuit for this relay becomes closed, which circuit is from the right-hand terminal of rectifier h2, through the winding of relay R1 and front contact 61 of relay R2 to the left-hand terminal of rectifier h2. The closing of relay R? opens at back contact 64 the stick circuit for relay R1, so that relay R1 then becomes de-energized, but relay R2 remains energized because its stick circuit is notcontrolled by relay R1. It will now be seen that the stick circuit for relay R1 includes back contacts of both relays R1 and R2, and, consequently, it will now be apparent why, as stated hereinbefore, relay R1 is not energized while relay R3 is energized. Relay R2 being energized, the approach restrict-ing lamp 42 of the` cab signal Q is lighted, because of a circuit which passesV from battery 28, through wires 58 and 60, back contact 46 of relay R3, front contact 35 of relay R2, lamp 42, and wire 59 to batso tery 28. Winding55 of magnet valve G is now energized by a circuit which passes from battery 28, throughfwires 58 and 62, front contact 36 of relay R2, wire 65, back contact 57 of relay S, contacts 52 and 53, winding 55 and wire 59 to battery 28. It follows that if the engineer has acknowledged the change in traffic conditions from clear to approach restricting, control relay R2 will be energized to prevent an automatic application of the brakes.

I will neXt assume that the supply of the approach restricting code is discontinued, and that the track rails are supplied with the approach code, so thatJ current of 80 cycles per minute is furnished by transformer T. Relay R2 now becomes cle-energized, because its associated circuit C2 is not tuned to current of 8O cycles per minute, with the result that the circuit last traced for winding of magnetvalve G becomes opened, and an automatic application of the brakes will occur unless the engineer acknowledges. If the engineer does acknowledge the change of indication, relay S will become energized by virtue of the same pick-up circuit as before, and after the release of the acknowledging switch this relay will remain energized by virtue of the same stick circuit as before. Relay R1 will then become energized by virtue of the same circuit as before, and will remain energized because its stick circuit remains closed at the back contacts of relays R2 and R1. With the relay R1 energized, the approach lamp 43 of the cab signal Q is lighted, the circuit beingl from battery 28, through wires 58 and 60 back contact 46 of relay R', back contact of relay R, front contact 37 of reaiyR1, lamp 43 and wire 59 to battery 28. gnet valve winding 55 is also energized by a circuit which passes from battery 28, throu h wires 58 and 63, front contact '38 of relay 1, wire 65, back contact 57 of relay S, contacts 52 and 53, winding 55 and wire 59 to battery 28. It is, of course, understood that as soon as relay R1 becomes energized, the acknowledging rela S o ens, because its stick circuit is opene at ack contact 37 of relay R1. l

I will now assume that the supply of track circuit current is discontinued to give the slow indication. Relay I) then ceases to operate, so that relay R1 becomes de-energized. The circuit last traced for magnet valve winding 55 is now opened at contact 38 of relay R1, so that unlessvthe engineer acknowledges, an automatic application of the brakes will occur. If the engineer does acknowledge, the acknowledging relay S will become closed and will remain closed by virtue of the same circuits as before, whereupon magnet valve Winding 55 will become energized by a circuit which passes from battery 28, through wire 58, front contact 57 of relay S, contacts 52 and 53, winding 55 and wire 59 to battery 28. The stick circuit for*` relay S remains closed, because the back contacts of relays R1, R2 and R3 are all closed, so'it follows that the train may proceed without incurring an automatic application of the brakes. Slow lamp 44 of cab signal Q is now lighted by virtue of a circuit which includes back contact 46 of relay R3, back contact 35 of relay R2 and back contact 37 of relay R1.

If now any one of the code frequencies is supplied to the track rails occupied by a train, the corresponding control relay R1, R2 or R3 will become energized by virtue of the circuits explained hereinbefore, it being apparent that acknowledgement is not necessary because acknowledging relay S is already energized.

In the event that the-engineer does not acknowledge a change from a more favorable to a less favorable indication the brakes will be applied and the train will be brought to a stop. The brakes may then be released by manual operation of the releasing switch r. When contact 106 of this switch is closed, a shunt is closed around acknowledging switch contact 71 and pneumatic relay contact 32, so that the pick-up circuit for acknowledging relay S will become closed. This will cause magnet valve Winding 55 to become energized, whereupon the brakes may be released and the train may proceed.

One feature of my invention is the provi sion of but one acknowledging relay S instead of the three acknowledging relays which are shown in the application by Lloyd V. Lewis referred to hereinbefore.

scribed only one form of apparatus embody mg my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what l claim is:

l. Train'carried traiic` governing apparatus comprising a circuit controlled from the trackway and at times carrying currents of three different frequencies, fsaid circuit having a first branch tuned to the first of said frequencies and a second branch tuned to the second of said frequencies each branch being provided 'with output terminals across which Aan appreciable voltage is impressed when and only when the circuit is supplied with current of the corresponding frequency, said circuit having a third branch provided with output terminals across which an appreciable voltage is impressed when the circuit is supplied with current of any of said frequencies; a rst, a second and a third control relay; a normally de-energized acknowledging relay, a manually operable acknowledging switch having a normally closed contact and a normally open contact, a pick-up circuit for said acknowledging relay including in series the normally open Contact of said acknowledging switch and a back contact of each of said control relays, a stick circuit for said acknowledging relay includinof in series a front contact of the acknowledging relay as well as a back contact of each of said control relays, a pick-up circuit for -said third control relay including the out-put terminals of said third branch and a front Contact of said acknowledging relay, a stick circuit for said third control relay including the output terminals ofsaidthird branch and a front contact of the third control relay as well as back contacts of said first and second control relays, a 'pick-up circuit for said second control relay including the out-put terminals of said second branch anda front contact of said third control relay, a stick circuit for said second control relay including the out-put 'terminals of said second branch and a front contact of said second control relay, a circuit for said first control relay including-the out-put terminals of said first branch, a brake controlling magnet, a circuit for said magnet including a back contact of said acknowledging relay and the normally closed contact of said acknowledging switch, said magnet circuit having three branches including front contacts of said three control relays respectively, and a second circuit for said brake magnet including a front contact of said acknowledging relay and the normally closed contact of said acknowledging switch.

2. Train carried ltraiiic governing apparatus comprising a first, a second, and a third pair of output terminals, means controlled from the trackway for at times creating a voltage across the terminals of one or more lof said pairs; a rst, a second, and a third control relay; a normally de-energized acknowledging relay, a manually operable acknowledging switch having a normally closed contact and a normally open contact, means for energizing said acknowledging relay when the normally open contact of said lacknowledging switch is closed and all three of said control relays are de-energized, means for keeping said acknowledging relay energized provided that all three of said control relays are de-energized, means for energizing said third control relay provided said acknowledging relay is energized and a volta e exists across said third pair of termina s, means for subsequently keeping said third control relay energized as long as the voltage exists across said third pair of terminals and the first and the second control relays are deenergized, means for energizing said second control relay provided said third control re ,across said second pair of terminals, means for energizing said first control relay when a voltage exists across said first pair of terminals, a brake controlling magnet, means for energizing said magnet when said acknowledging rela is de-energized and the normally close contact of said. acknowledging switch is closed provided that any one of said control relays is energized, and means for energizing said brake controlling magnet when said acknowledging relay is energized and the normally closed contact of said acknowledging switch is closed.

3. Train carried traiiic governing apparatus comprising a rst, a second, and a third pair of out-put terminals, means controlled from the trackway for at times creating a voltage across the terminals of'oneo more of said pairs; a rst,'a second, and a third control relay; a normally deenergized acknowledging relay, a manually operable acknowledging switch having a normally closed contact and a normally open contact, a pickup circuit for said acknowledging relay including in series a normally open contact of said acknowledging switch and a back contact of each of said control relays, a stick circuit for said acknowledging relay including in series a front contact of the acknowledging relay as well as a back contact of each of said control relays, a pick-up circuit for said third control relay includingr the third pair of out-put terminals and a iront contact of said acknowledging relay, a stick circuit for 'said third control relay including said third pair of voutput terminals and a front contact of the third control relay as well as a back contact of the second control relayT and a back contact of the first control relay, a pick-up circuit for said second control 'relay including the second pair of out-put terminals and a front contact of said third control relay, a stick circuit for said second control relay including the second pair of out-put terminals and a front contact of the second control relay, a circuit for said first control o relay including the first pair of out-put terminals, a brake controlling magnet, a circuit for said magnet including a back contact of said acknowledging relay and a normally closed contact of said acknowledging switch, said magnet circuit having three branches including front contacts of said three control relays respectively, and a second circuit for said brake magnet including a front contact of said acknowledging relay and a normally closed contact of said acknowledging switch.

4. Train carried traffic governing apparatus comprising two pairs of out-put terminals, means controlled from the trackway for at times creating a voltage across the z5 terminals of one or both of said pairs,

a first and a second control relay, a normally de-cnergized acknowledging relay, a manually operable acknowledging switch having a normally closed contact and ,o a normally open Contact, means for energizing said acknowledging relay when the normally open Contact of said acknowledging switch is closed and both of said control relays are cle-energized, means for subsequently keeping said acknowledging relay energized as long as both of said control relays are de-energized, means for energizing said second control relay when a voltage exists across said second pair of out-put terminals and said acknowledging relay is energized, means for subsequently keeping said second control relay energized as long as voltage exists across said second pair of out-put terminals and the first control relay is de-energized, means for energizing said first control relay when voltage exists across the first pair of out-upt terminals and the second control relay is energized, means for subsequently keeping said first control relay energized as long as Vvoltage exists across said first pair of out-put terminals, a brake controlling magnet, means for energizing said brake controlling magnet when said acknowledging relay is cle-energized and the normally closed contact of said acknowledging switch is closed provided that one or both of said control relays are energized and means for energizing said brake controlling magnet when said acknowledging relay is energized and n the normally closed contact of said acknowledging switch is closed.

5. Train carried traiiic governing apparatus comprising a first, a second, and a third control relay, a normally de-energized aci knowledging relay, a manually operable acknowledging switch having a normally closed contact and a normally o en contact, a ickup circuit for said acknow edging relayI c osed only when all three of said control re ays are de-energized and the normally o en contact of said acknowledging switch 1s closed, a stick circuit for said acknowledging relay closed only when the acknowledging relay is closed and all three of said control relays are de-energized, a pick-up circuit for said third control relay including a front contact of said acknowledging relay, a stick circuit for said third control relay including a front contact of the third control relay as well as back contacts of said first and second control relays, apick-up circuit for said secondy control relay including a front Contact of said third control relay, a stick circuit for said second control relay including a front contact of the second control relay, a circuit for said first control relay, a brake controlling magnet, means for energizing said magnet when said acknowledging relay or any one of said control relays is energized, and means for selectively supplying current to the circuits for any one or more of said control rela s.

`-)ln testimony whereof I aix my signature.

RONALD A MOCANN. 

